SUBSTITUTION, IDENTIFICATION, UNION
That if thou shalt confess with thy mouth the Lord Jesus and shalt believe in thine heart that God hath raised Him from the dead, thou shalt be saved. For with the heart man believeth unto righteousness and with the mouth confession is made unto salvation. (Romans 10:9-10)
Your identification with Christ is activated by your identical confession of faith of who you are in Christ.
Everything Jesus did, He did for you; it is set to the credit of your account as though you did it. This is the progression from substitution to identification and union with Christ. When someone is born again, He is a new creature in Christ Jesus; old things are passed away and everything is new. (2 Corinthians 5:17) God would not make an unrighteous new creature. If you are saved, you must be righteous.
When Jesus was raised from the dead, you were justified or declared righteous. You could even say that Jesus was not raised from the dead until you were declared righteous. The penalty for sin was paid in full and God declared you righteous. This is the reason the Gospel is good news to every person!
Confession: The penalty for sin was paid in full and God has declared me righteous!